Actually, they probably weren't convicted in trials, especially if their crimes were federal. 90% of them are probably there due to taking a plea bargain. They may or may not be guilty, since plea bargaining makes a guilty plea with a lighter sentence more attractive than proving your own innocence in a way that guarantees financial ruin and risks an extremely harsh sentence.

I will slap my wife a little, here and there, not much, she deserves it, but damn, have you seen what Joe have done to his wife, he broke her arm and sent her to hospital, he is a monster!